While Antonio Valencia has been Mourinho’s first-choice on the right, he has used Matteo Darmian, Marcos Rojo, Daley Blind, Ashley Young and Luke Shaw on the other side. Even Henrikh Mkhitaryan has filled in on occasion.

It is, though, Shaw’s situation that is most relevant. At his best, he is not unlike Alba.

Quick, tenacious and aggressive like all good attacking full-backs, he was considered a sound investment when he arrived as a teenager from Southampton in the summer of 2014.

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The decision, then, will lie with Shaw, who is under contract until at least 2018, and whether he believes he will get regular football under Mourinho. There will be plenty of Premier League suitors if not.

All the while, Alba’s situation in Barcelona will intrigue United.

Seemingly unsettled at Camp Nou there may be a small window of opportunity to persuade the Spaniard he would be better off at Old Trafford.

The prospect of playing for United, and for Mourinho, is said to interest the 28-year-old. But then they were told the same about Sergio Ramos in 2015 and the chase ended in calamity.

United and Ed Woodward will be keen to avoid a similar situation.

But they are in the business of signing world class players. And there may be an opening at left-back this summer.